/lib/ddl/postgres_sql_generator.php
PHP | 535 lines | 291 code | 57 blank | 187 comment | 83 complexity | 917c3367dc0c2f4f30d67da6e3d5b0c1 MD5 | raw file
- <?php
- // This file is part of Moodle - http://moodle.org/
- //
- // Moodle is free software: you can redistribute it and/or modify
- // it under the terms of the GNU General Public License as published by
- // the Free Software Foundation, either version 3 of the License, or
- // (at your option) any later version.
- //
- // Moodle is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU General Public License for more details.
- //
- // You should have received a copy of the GNU General Public License
- // along with Moodle. If not, see <http://www.gnu.org/licenses/>.
- /**
- * PostgreSQL specific SQL code generator.
- *
- * @package core_ddl
- * @copyright 1999 onwards Martin Dougiamas http://dougiamas.com
- * 2001-3001 Eloy Lafuente (stronk7) http://contiento.com
- * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
- defined('MOODLE_INTERNAL') || die();
- require_once($CFG->libdir.'/ddl/sql_generator.php');
- /**
- * This class generate SQL code to be used against PostgreSQL
- * It extends XMLDBgenerator so everything can be
- * overridden as needed to generate correct SQL.
- *
- * @package core_ddl
- * @copyright 1999 onwards Martin Dougiamas http://dougiamas.com
- * 2001-3001 Eloy Lafuente (stronk7) http://contiento.com
- * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
- class postgres_sql_generator extends sql_generator {
- // Only set values that are different from the defaults present in XMLDBgenerator
- /** @var string Proper type for NUMBER(x) in this DB. */
- public $number_type = 'NUMERIC';
- /** @var string To define the default to set for NOT NULLs CHARs without default (null=do nothing).*/
- public $default_for_char = '';
- /** @var bool True if the generator needs to add extra code to generate the sequence fields.*/
- public $sequence_extra_code = false;
- /** @var string The particular name for inline sequences in this generator.*/
- public $sequence_name = 'BIGSERIAL';
- /** @var string The particular name for inline sequences in this generator.*/
- public $sequence_name_small = 'SERIAL';
- /** @var bool To avoid outputting the rest of the field specs, leaving only the name and the sequence_name returned.*/
- public $sequence_only = true;
- /** @var string SQL sentence to rename one index where 'TABLENAME', 'OLDINDEXNAME' and 'NEWINDEXNAME' are dynamically replaced.*/
- public $rename_index_sql = 'ALTER TABLE OLDINDEXNAME RENAME TO NEWINDEXNAME';
- /** @var string SQL sentence to rename one key 'TABLENAME', 'OLDKEYNAME' and 'NEWKEYNAME' are dynamically replaced.*/
- public $rename_key_sql = null;
- /** @var string type of string quoting used - '' or \' quotes*/
- protected $std_strings = null;
- /**
- * Reset a sequence to the id field of a table.
- *
- * @param xmldb_table|string $table name of table or the table object.
- * @return array of sql statements
- */
- public function getResetSequenceSQL($table) {
- if ($table instanceof xmldb_table) {
- $tablename = $table->getName();
- } else {
- $tablename = $table;
- }
- // From http://www.postgresql.org/docs/7.4/static/sql-altersequence.html
- $value = (int)$this->mdb->get_field_sql('SELECT MAX(id) FROM {'.$tablename.'}');
- $value++;
- return array("ALTER SEQUENCE $this->prefix{$tablename}_id_seq RESTART WITH $value");
- }
- /**
- * Given one correct xmldb_table, returns the SQL statements
- * to create temporary table (inside one array).
- *
- * @param xmldb_table $xmldb_table The xmldb_table object instance.
- * @return array of sql statements
- */
- public function getCreateTempTableSQL($xmldb_table) {
- $this->temptables->add_temptable($xmldb_table->getName());
- $sqlarr = $this->getCreateTableSQL($xmldb_table);
- $sqlarr = preg_replace('/^CREATE TABLE/', "CREATE TEMPORARY TABLE", $sqlarr);
- return $sqlarr;
- }
- /**
- * Given one correct xmldb_table, returns the SQL statements
- * to drop it (inside one array).
- *
- * @param xmldb_table $xmldb_table The table to drop.
- * @return array SQL statement(s) for dropping the specified table.
- */
- public function getDropTableSQL($xmldb_table) {
- $sqlarr = parent::getDropTableSQL($xmldb_table);
- if ($this->temptables->is_temptable($xmldb_table->getName())) {
- $this->temptables->delete_temptable($xmldb_table->getName());
- }
- return $sqlarr;
- }
- /**
- * Given one correct xmldb_index, returns the SQL statements
- * needed to create it (in array).
- *
- * @param xmldb_table $xmldb_table The xmldb_table instance to create the index on.
- * @param xmldb_index $xmldb_index The xmldb_index to create.
- * @return array An array of SQL statements to create the index.
- * @throws coding_exception Thrown if the xmldb_index does not validate with the xmldb_table.
- */
- public function getCreateIndexSQL($xmldb_table, $xmldb_index) {
- $sqls = parent::getCreateIndexSQL($xmldb_table, $xmldb_index);
- $hints = $xmldb_index->getHints();
- $fields = $xmldb_index->getFields();
- if (in_array('varchar_pattern_ops', $hints) and count($fields) == 1) {
- // Add the pattern index and keep the normal one, keep unique only the standard index to improve perf.
- foreach ($sqls as $sql) {
- $field = reset($fields);
- $count = 0;
- $newindex = preg_replace("/^CREATE( UNIQUE)? INDEX ([a-z0-9_]+) ON ([a-z0-9_]+) \($field\)$/", "CREATE INDEX \\2_pattern ON \\3 USING btree ($field varchar_pattern_ops)", $sql, -1, $count);
- if ($count != 1) {
- debugging('Unexpected getCreateIndexSQL() structure.');
- continue;
- }
- $sqls[] = $newindex;
- }
- }
- return $sqls;
- }
- /**
- * Given one XMLDB Type, length and decimals, returns the DB proper SQL type.
- *
- * @param int $xmldb_type The xmldb_type defined constant. XMLDB_TYPE_INTEGER and other XMLDB_TYPE_* constants.
- * @param int $xmldb_length The length of that data type.
- * @param int $xmldb_decimals The decimal places of precision of the data type.
- * @return string The DB defined data type.
- */
- public function getTypeSQL($xmldb_type, $xmldb_length=null, $xmldb_decimals=null) {
- switch ($xmldb_type) {
- case XMLDB_TYPE_INTEGER: // From http://www.postgresql.org/docs/7.4/interactive/datatype.html
- if (empty($xmldb_length)) {
- $xmldb_length = 10;
- }
- if ($xmldb_length > 9) {
- $dbtype = 'BIGINT';
- } else if ($xmldb_length > 4) {
- $dbtype = 'INTEGER';
- } else {
- $dbtype = 'SMALLINT';
- }
- break;
- case XMLDB_TYPE_NUMBER:
- $dbtype = $this->number_type;
- if (!empty($xmldb_length)) {
- $dbtype .= '(' . $xmldb_length;
- if (!empty($xmldb_decimals)) {
- $dbtype .= ',' . $xmldb_decimals;
- }
- $dbtype .= ')';
- }
- break;
- case XMLDB_TYPE_FLOAT:
- $dbtype = 'DOUBLE PRECISION';
- if (!empty($xmldb_decimals)) {
- if ($xmldb_decimals < 6) {
- $dbtype = 'REAL';
- }
- }
- break;
- case XMLDB_TYPE_CHAR:
- $dbtype = 'VARCHAR';
- if (empty($xmldb_length)) {
- $xmldb_length='255';
- }
- $dbtype .= '(' . $xmldb_length . ')';
- break;
- case XMLDB_TYPE_TEXT:
- $dbtype = 'TEXT';
- break;
- case XMLDB_TYPE_BINARY:
- $dbtype = 'BYTEA';
- break;
- case XMLDB_TYPE_DATETIME:
- $dbtype = 'TIMESTAMP';
- break;
- }
- return $dbtype;
- }
- /**
- * Returns the code (array of statements) needed to add one comment to the table.
- *
- * @param xmldb_table $xmldb_table The xmldb_table object instance.
- * @return array Array of SQL statements to add one comment to the table.
- */
- function getCommentSQL ($xmldb_table) {
- $comment = "COMMENT ON TABLE " . $this->getTableName($xmldb_table);
- $comment.= " IS '" . $this->addslashes(substr($xmldb_table->getComment(), 0, 250)) . "'";
- return array($comment);
- }
- /**
- * Returns the code (array of statements) needed to execute extra statements on table rename.
- *
- * @param xmldb_table $xmldb_table The xmldb_table object instance.
- * @param string $newname The new name for the table.
- * @return array Array of extra SQL statements to rename a table.
- */
- public function getRenameTableExtraSQL($xmldb_table, $newname) {
- $results = array();
- $newt = new xmldb_table($newname);
- $xmldb_field = new xmldb_field('id'); // Fields having sequences should be exclusively, id.
- $oldseqname = $this->getTableName($xmldb_table) . '_' . $xmldb_field->getName() . '_seq';
- $newseqname = $this->getTableName($newt) . '_' . $xmldb_field->getName() . '_seq';
- // Rename de sequence
- $results[] = 'ALTER TABLE ' . $oldseqname . ' RENAME TO ' . $newseqname;
- return $results;
- }
- /**
- * Given one xmldb_table and one xmldb_field, return the SQL statements needed to alter the field in the table.
- *
- * PostgreSQL has some severe limits:
- * - Any change of type or precision requires a new temporary column to be created, values to
- * be transfered potentially casting them, to apply defaults if the column is not null and
- * finally, to rename it
- * - Changes in null/not null require the SET/DROP NOT NULL clause
- * - Changes in default require the SET/DROP DEFAULT clause
- *
- * @param xmldb_table $xmldb_table The table related to $xmldb_field.
- * @param xmldb_field $xmldb_field The instance of xmldb_field to create the SQL from.
- * @param string $skip_type_clause The type clause on alter columns, NULL by default.
- * @param string $skip_default_clause The default clause on alter columns, NULL by default.
- * @param string $skip_notnull_clause The null/notnull clause on alter columns, NULL by default.
- * @return string The field altering SQL statement.
- */
- public function getAlterFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause = NULL, $skip_default_clause = NULL, $skip_notnull_clause = NULL) {
- $results = array(); // To store all the needed SQL commands
- // Get the normal names of the table and field
- $tablename = $xmldb_table->getName();
- $fieldname = $xmldb_field->getName();
- // Take a look to field metadata
- $meta = $this->mdb->get_columns($tablename);
- $metac = $meta[$xmldb_field->getName()];
- $oldmetatype = $metac->meta_type;
- $oldlength = $metac->max_length;
- $olddecimals = empty($metac->scale) ? null : $metac->scale;
- $oldnotnull = empty($metac->not_null) ? false : $metac->not_null;
- $olddefault = empty($metac->has_default) ? null : $metac->default_value;
- $typechanged = true; //By default, assume that the column type has changed
- $precisionchanged = true; //By default, assume that the column precision has changed
- $decimalchanged = true; //By default, assume that the column decimal has changed
- $defaultchanged = true; //By default, assume that the column default has changed
- $notnullchanged = true; //By default, assume that the column notnull has changed
- // Detect if we are changing the type of the column
- if (($xmldb_field->getType() == XMLDB_TYPE_INTEGER && $oldmetatype == 'I') ||
- ($xmldb_field->getType() == XMLDB_TYPE_NUMBER && $oldmetatype == 'N') ||
- ($xmldb_field->getType() == XMLDB_TYPE_FLOAT && $oldmetatype == 'F') ||
- ($xmldb_field->getType() == XMLDB_TYPE_CHAR && $oldmetatype == 'C') ||
- ($xmldb_field->getType() == XMLDB_TYPE_TEXT && $oldmetatype == 'X') ||
- ($xmldb_field->getType() == XMLDB_TYPE_BINARY && $oldmetatype == 'B')) {
- $typechanged = false;
- }
- // Detect if we are changing the precision
- if (($xmldb_field->getType() == XMLDB_TYPE_TEXT) ||
- ($xmldb_field->getType() == XMLDB_TYPE_BINARY) ||
- ($oldlength == -1) ||
- ($xmldb_field->getLength() == $oldlength)) {
- $precisionchanged = false;
- }
- // Detect if we are changing the decimals
- if (($xmldb_field->getType() == XMLDB_TYPE_INTEGER) ||
- ($xmldb_field->getType() == XMLDB_TYPE_CHAR) ||
- ($xmldb_field->getType() == XMLDB_TYPE_TEXT) ||
- ($xmldb_field->getType() == XMLDB_TYPE_BINARY) ||
- (!$xmldb_field->getDecimals()) ||
- (!$olddecimals) ||
- ($xmldb_field->getDecimals() == $olddecimals)) {
- $decimalchanged = false;
- }
- // Detect if we are changing the default
- if (($xmldb_field->getDefault() === null && $olddefault === null) ||
- ($xmldb_field->getDefault() === $olddefault)) {
- $defaultchanged = false;
- }
- // Detect if we are changing the nullability
- if (($xmldb_field->getNotnull() === $oldnotnull)) {
- $notnullchanged = false;
- }
- // Get the quoted name of the table and field
- $tablename = $this->getTableName($xmldb_table);
- $fieldname = $this->getEncQuoted($xmldb_field->getName());
- // Decide if we have changed the column specs (type/precision/decimals)
- $specschanged = $typechanged || $precisionchanged || $decimalchanged;
- // if specs have changed, need to alter column
- if ($specschanged) {
- // Always drop any exiting default before alter column (some type changes can cause casting error in default for column)
- if ($olddefault !== null) {
- $results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP DEFAULT'; // Drop default clause
- }
- $alterstmt = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $this->getEncQuoted($xmldb_field->getName()) .
- ' TYPE' . $this->getFieldSQL($xmldb_table, $xmldb_field, null, true, true, null, false);
- // Some castings must be performed explicitly (mainly from text|char to numeric|integer)
- if (($oldmetatype == 'C' || $oldmetatype == 'X') &&
- ($xmldb_field->getType() == XMLDB_TYPE_NUMBER || $xmldb_field->getType() == XMLDB_TYPE_FLOAT)) {
- $alterstmt .= ' USING CAST('.$fieldname.' AS NUMERIC)'; // from char or text to number or float
- } else if (($oldmetatype == 'C' || $oldmetatype == 'X') &&
- $xmldb_field->getType() == XMLDB_TYPE_INTEGER) {
- $alterstmt .= ' USING CAST(CAST('.$fieldname.' AS NUMERIC) AS INTEGER)'; // From char to integer
- }
- $results[] = $alterstmt;
- }
- // If the default has changed or we have performed one change in specs
- if ($defaultchanged || $specschanged) {
- $default_clause = $this->getDefaultClause($xmldb_field);
- if ($default_clause) {
- $sql = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' SET' . $default_clause; // Add default clause
- $results[] = $sql;
- } else {
- if (!$specschanged) { // Only drop default if we haven't performed one specs change
- $results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP DEFAULT'; // Drop default clause
- }
- }
- }
- // If the not null has changed
- if ($notnullchanged) {
- if ($xmldb_field->getNotnull()) {
- $results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' SET NOT NULL';
- } else {
- $results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP NOT NULL';
- }
- }
- // Return the results
- return $results;
- }
- /**
- * Given one xmldb_table and one xmldb_field, return the SQL statements needed to add its default
- * (usually invoked from getModifyDefaultSQL()
- *
- * @param xmldb_table $xmldb_table The xmldb_table object instance.
- * @param xmldb_field $xmldb_field The xmldb_field object instance.
- * @return array Array of SQL statements to create a field's default.
- */
- public function getCreateDefaultSQL($xmldb_table, $xmldb_field) {
- // Just a wrapper over the getAlterFieldSQL() function for PostgreSQL that
- // is capable of handling defaults
- return $this->getAlterFieldSQL($xmldb_table, $xmldb_field);
- }
- /**
- * Given one xmldb_table and one xmldb_field, return the SQL statements needed to drop its default
- * (usually invoked from getModifyDefaultSQL()
- *
- * Note that this method may be dropped in future.
- *
- * @param xmldb_table $xmldb_table The xmldb_table object instance.
- * @param xmldb_field $xmldb_field The xmldb_field object instance.
- * @return array Array of SQL statements to create a field's default.
- *
- * @todo MDL-31147 Moodle 2.1 - Drop getDropDefaultSQL()
- */
- public function getDropDefaultSQL($xmldb_table, $xmldb_field) {
- // Just a wrapper over the getAlterFieldSQL() function for PostgreSQL that
- // is capable of handling defaults
- return $this->getAlterFieldSQL($xmldb_table, $xmldb_field);
- }
- /**
- * Adds slashes to string.
- * @param string $s
- * @return string The escaped string.
- */
- public function addslashes($s) {
- // Postgres is gradually switching to ANSI quotes, we need to check what is expected
- if (!isset($this->std_strings)) {
- $this->std_strings = ($this->mdb->get_field_sql("select setting from pg_settings where name = 'standard_conforming_strings'") === 'on');
- }
- if ($this->std_strings) {
- $s = str_replace("'", "''", $s);
- } else {
- // do not use php addslashes() because it depends on PHP quote settings!
- $s = str_replace('\\','\\\\',$s);
- $s = str_replace("\0","\\\0", $s);
- $s = str_replace("'", "\\'", $s);
- }
- return $s;
- }
- /**
- * Given one xmldb_table returns one string with the sequence of the table
- * in the table (fetched from DB)
- * The sequence name for Postgres has one standard name convention:
- * tablename_fieldname_seq
- * so we just calculate it and confirm it's present in pg_class
- *
- * @param xmldb_table $xmldb_table The xmldb_table object instance.
- * @return string|bool If no sequence is found, returns false
- */
- function getSequenceFromDB($xmldb_table) {
- $tablename = $this->getTableName($xmldb_table);
- $sequencename = $tablename . '_id_seq';
- if (!$this->mdb->get_record_sql("SELECT c.*
- FROM pg_catalog.pg_class c
- JOIN pg_catalog.pg_namespace as ns ON ns.oid = c.relnamespace
- WHERE c.relname = ? AND c.relkind = 'S'
- AND (ns.nspname = current_schema() OR ns.oid = pg_my_temp_schema())",
- array($sequencename))) {
- $sequencename = false;
- }
- return $sequencename;
- }
- /**
- * Given one object name and it's type (pk, uk, fk, ck, ix, uix, seq, trg).
- *
- * (MySQL requires the whole xmldb_table object to be specified, so we add it always)
- *
- * This is invoked from getNameForObject().
- * Only some DB have this implemented.
- *
- * @param string $object_name The object's name to check for.
- * @param string $type The object's type (pk, uk, fk, ck, ix, uix, seq, trg).
- * @param string $table_name The table's name to check in
- * @return bool If such name is currently in use (true) or no (false)
- */
- public function isNameInUse($object_name, $type, $table_name) {
- switch($type) {
- case 'ix':
- case 'uix':
- case 'seq':
- if ($check = $this->mdb->get_records_sql("SELECT c.relname
- FROM pg_class c
- JOIN pg_catalog.pg_namespace as ns ON ns.oid = c.relnamespace
- WHERE lower(c.relname) = ?
- AND (ns.nspname = current_schema() OR ns.oid = pg_my_temp_schema())", array(strtolower($object_name)))) {
- return true;
- }
- break;
- case 'pk':
- case 'uk':
- case 'fk':
- case 'ck':
- if ($check = $this->mdb->get_records_sql("SELECT c.conname
- FROM pg_constraint c
- JOIN pg_catalog.pg_namespace as ns ON ns.oid = c.connamespace
- WHERE lower(c.conname) = ?
- AND (ns.nspname = current_schema() OR ns.oid = pg_my_temp_schema())", array(strtolower($object_name)))) {
- return true;
- }
- break;
- case 'trg':
- if ($check = $this->mdb->get_records_sql("SELECT tgname
- FROM pg_trigger
- WHERE lower(tgname) = ?", array(strtolower($object_name)))) {
- return true;
- }
- break;
- }
- return false; //No name in use found
- }
- /**
- * Returns an array of reserved words (lowercase) for this DB
- * @return array An array of database specific reserved words
- */
- public static function getReservedWords() {
- // This file contains the reserved words for PostgreSQL databases
- // This file contains the reserved words for PostgreSQL databases
- // http://www.postgresql.org/docs/current/static/sql-keywords-appendix.html
- $reserved_words = array (
- 'all', 'analyse', 'analyze', 'and', 'any', 'array', 'as', 'asc',
- 'asymmetric', 'authorization', 'between', 'binary', 'both', 'case',
- 'cast', 'check', 'collate', 'column', 'constraint', 'create', 'cross',
- 'current_date', 'current_role', 'current_time', 'current_timestamp',
- 'current_user', 'default', 'deferrable', 'desc', 'distinct', 'do',
- 'else', 'end', 'except', 'false', 'for', 'foreign', 'freeze', 'from',
- 'full', 'grant', 'group', 'having', 'ilike', 'in', 'initially', 'inner',
- 'intersect', 'into', 'is', 'isnull', 'join', 'leading', 'left', 'like',
- 'limit', 'localtime', 'localtimestamp', 'natural', 'new', 'not',
- 'notnull', 'null', 'off', 'offset', 'old', 'on', 'only', 'or', 'order',
- 'outer', 'overlaps', 'placing', 'primary', 'references', 'returning', 'right', 'select',
- 'session_user', 'similar', 'some', 'symmetric', 'table', 'then', 'to',
- 'trailing', 'true', 'union', 'unique', 'user', 'using', 'verbose',
- 'when', 'where', 'with'
- );
- return $reserved_words;
- }
- }